Examples of known portable toilets to which the present invention relates are disclosed in U.S. Pat. No. 3,570,018, patented Mar. 16, 1971 in the names of Sargent et al; U.S. Pat. No. 3,949,430, patented Apr. 13, 1976 in the names of Miller et al; and U.S. Pat. No. 4,145,773, patented Mar. 27, 1979 in the names of Sargent et al.
Portable toilets of this character have holding tanks on which are removably mounted upper units which contain among other items, the toilet bowl, a flush water storage tank and flush apparatus for flushing waste material from the bowl into the holding tank. It is the conventional practice in each of the toilets disclosed in U.S. Pat. Nos. 3,949,430 and 4,145,773 to provide a valve assembly that is located within the holding tank for opening and closing the tank inlet port which is in communication with the outlet port of the toilet bowl. It is also known to provide a vent means for the holding tank to equalize the atmospheric and holding tank pressures before opening and closing the inlet port to the holding tank, as is disclosed in U.S. Pat. No. 4,145,773.
In portable toilets of this character, individual handles are provided for carrying the holding tank section and the upper section separately, and the sections can be carried in stacked-together relationship by clamping the sections together and then carrying the toilets by either one or the other of the handles. These toilets necessarily require clamping mechanisms of sturdy construction to retain the sections together if they are to be transported in this manner under adverse conditions.
Relatively simple flush apparatus is also provided in the prior art toilets wherein hand actuated bellows pumps are located in an upper portion of the upper section adjacent to the toilet seat for pumping the flush water from the storage tank into the toilet bowl. Because of the portable nature of the toilets, the column of water in the conduit from the flush water storage tank to the pump is often broken so that before the toilet can be flushed the pump must be primed by repeated pumping action of the bellows pump.